In large bowl, beat butter with shortening; beat in granulated and brown sugars. Beat in eggs 1 at a time, and vanilla.
Whisk together flour, baking soda and salt; blend into creamed mixture. Stir in nuts and chocolate chips. Refrigerate dough for 15 minutes.
Using fingertips, spread dough evenly into greased 15- x 10-inch jelly roll pan. Bake in 375°F oven until golden brown and still slightly underbaked in centre, 18 to 20 minutes.
Let cool slightly in pan on rack; cut into bars while still warm. Let cool completely before removing from pan.
To toast hazelnuts: Spread on baking sheet and bake in 350°F oven until golden and fragrant, 8 to 10 minutes. Transfer to tea towel; fold over and rub vigorously to remove as much of the skins as possible. Let cool; chop.